Friday, January 1, 2021

What to do when OpenRocket no longer works...

Some of you may know that I switched from Windows/PCs to MacOS/Macs several years ago - I got tired of all the issues with drivers, the "blue screens of death", the endless stream of updates, and the relentless virus/malware attacks. However, this change came with costs - the first being that Macs are very expensive compared to the equivalent PC in terms of horsepower. There is also less software available, especially in the engineering area, and you pretty much sell your soul to Apple. Microsoft only wants to own your computer's operating system - Apple takes the whole shooting match, hardware and OS. But I will say that things work very well the vast majority of the time - practically no system crashes, and the software that is available works smoothly and has a "better polish" than the Windows equivalent. I have had no problems with software from the Apple App Store; it's only the stuff one downloads that causes the fits.

Which brings me to OpenRocket...

On all my past Macs (including my MacBook Air laptop), OpenRocket has worked flawlessly; it even worked fine on my new Mac until yesterday, when I upgraded the operating system from Catalina (10.15) to Big Sur (11.1). I did the usual reinstall of Java you have to do when you perform such an upgrade, checked to make sure the Java was working, and then fired up OpenRocket as a test. That's when I saw this:

Well, crap.

I spent the next couple hours googling and trying things with permissions and stuff - nothing worked. My frustration mounted, and I began to understand the feelings of TARC newbies who struggle to get OpenRocket working on their computers. I had often shrugged off their issues by telling them their Java installs were not right, and that if Java was working, there would be no problems with OpenRocket. Well, darn it, my Java was working and the stupid program would not run! I can tell you, I will be much more sympathetic in the future.

For a few minutes, I thought OpenRocket's performances on the screen of my shiny new Mac were a thing of the past, and that I would have to run it on my laptop (which I am not going to upgrade to Big Sur anytime soon!). Then my searching revealed this page, in which someone had posted links to OpenRocket run times and executables compiled for different operating systems. I downloaded the MacOS version, and voila! OpenRocket once again graced the screen of my Mac!

Big sigh of relief.

However, this whole experience once again drove home the fact that major updates to our computer operating systems, driven by security and technology advances, are just as, if not more, frequent than software updates. This is especially true for hobby programs like OpenRocket, which hasn't been updated since 2015, and also for altimeter drivers/codes like those from PerfectFlite. Keeping these legacy codes running often involves hacks or bypassing OS security features, and eventually things reach a point where even that is not enough. Catalina did that to me, as 32 bit codes no longer work. Unlike Microsoft, which provided a fair amount of backwards compatibility, Apple simply forced developers to upgrade their programs to 64 bits. So now I have to find a Windows box to download data from my Perfectflite PNUT. This is the major reason I have largely switched to Bluetooth altimeters like the FlightSketch, as small vendors like PerfectFlite focus on the Windows platform, which is over 90% of the market. Macs are an afterthought, if there is a thought.

I understand that we can expect a new version of OpenRocket sometime in the foreseeable future, which would make me quite happy. It's a great program and needs to be maintained/upgraded.

Back to designing rockets...

Thursday, December 31, 2020

Bye Bye 2020!

Can't say I'll be sorry to see you gone... COVID-19 wreaked havoc on the world, causing many deaths, lost livelihoods, business failures, and radical changes in our daily lives. It also impacted the rocketry hobby, causing the cancellation of launches and a shift to online meetings. In addition to this plague, we had to deal with considerable bad weather - my goodness, the number of hurricanes! Hard to imagine a worse year.

Hoping 2021 turns out to be much better!

Saturday, November 28, 2020


I only made 2 flights at the November HARA launch; the first was that of the RX-16, described in the last post, and the second was the maiden flight of my Quest Q E-Z Payloader, a "Qwik Kit" I acquired many moons ago. It was recommended by Art Upton as a good starting rocket to loft his BoosterVision Mini GearCam, a 2.4 GHz camera that live-streamed the video to a receiver, much like the way it is done by NASA, Space X and ULA. While I tested the GearCam on the ground, I never got around to flying it - and for the life of me, I can't remember why. Anyway, the Q E-Z Payloader has sat on the shelf for over a decade, until I decided to launch it two weekends ago.

Quest Q E-Z Payloader (Click to enlarge).

And the rocket did carry a camera, even though it was not the one for which it was purchased. I taped the Estes camera to the side of the payload section, and, just to make things more nerdy, loaded a Perfectflite PNUT into the compartment. A quick weight check indicated that an Estes C6-5 would be about perfect for the flight - I estimated a peak altitude of around 350 feet, which was high enough to get good footage, but not so high as to make for a long walk. Yep, I had thought things through and prepared pretty well.

Uh huh...

The Q E-Z Payloader left the pad and headed up into the blue sky. I watched it arc over and was pleased to see the nylon Apogee chute deploy. But then I caught a glimpse of other pieces falling, and that's when it hit me...

I had forgotten to tape the nose cone to the payload tube, so it would stay in place throughout the flight.

So those two additional falling pieces were the nose cone (no big deal) and the PNUT altimeter (big deal, to the tune of $60). And I did not see where they landed, so I did not have a location to search.

Sighing, I trudged after the rocket, having little hope of recovering the nose cone or, more importantly, the altimeter (assuming it survived the fall). But fortune did smile upon me, for as I was returning to the flight line one of the rocketeers at the high power pads handed me the altimeter. He had heard it beeping - PNUTs are noisy little beasties - and located it on the ground using the sound. I also got back the nose cone, which was a minor miracle. The model has been put back on the shelf, ready for its next flight. And I hope to not be as stupid for that one.

Anyway, I downloaded the data from the altimeter - which appears to be undamaged, as it fell in its holder tube - and got an answer to the question "What does an altimeter record as it is free falling to the ground?" Apparently the tumbling results in oscillations, as you can see from the below graph. The altimeter was also not as snug in the holder tube as I would have liked, and that also shows in the flight profile. At least my motor choice was correct.

Q E-Z Payloader flight profile from November HARA launch (Click to enlarge).

Being taped to the side of the payload section, the camera stayed with the rocket, and I managed to pull a few interesting frames from the video:

Ignition (Click to enlarge)!

Coasting upward (Click to enlarge).

Parachute deploy (Click to enlarge).

Altimeter and nose cone falling away (Click to enlarge).

So a good ending came out of a royal screw-up on my part. That does not happen often.

Comparing instruments...

Today's electronics are wonderful; you can fit a lot of measurement capability into a very small package. There are a goodly number of choices available from various vendors and it is a very natural thing to compare capabilities and accuracy, especially when new products hit the market. That's one reason I built the clone of the Centuri RX-16 and the beefy Big Bertha look-a-like, Beulah. Their large payload sections and interchangeable motor mounts enable me to fly multiple instruments on the same flight, facilitating comparisons.

PocketLab Voyager

I was perusing the Estes website last month, and came across these teacher's bundles, which feature the large 24mm powered Green Eggs rocket and some electronics gizmo called the PocketLab. The prices were a little rich for my wallet, but I was intrigued by the PocketLab - I had not heard of it. A Google search instantly produced the manufacturer's website, where I learned that the PocketLab included in the Estes bundles was the PocketLab Voyager, a 1.5 x 1.5 x 0.6 inch mini laboratory capable of making measurements of the following:

  • Acceleration
  • Angular Velocity
  • Magnetic Field
  • Barometric Pressure
  • Altitude
  • Infrared Rangefinder
  • Internal Temperature
  • Temperature Probe
  • Humidity
  • Light Intensity
Wowzers! This is a lot of capability, and after perusing the online documentation, I figured I ought to get one - in the interest of science, of course. I never play... Anyway, the PocketLab Voyager arrived within a few days, and quick trial and error showed that it would fit - albeit very tightly - in the 1.6 inch diameter Estes BT-60 body tube (the Green Eggs rocket that Estes bundled with the Voyager is 1.8" in diameter). I was happy, as this meant I could use the RX-16 or Beulah to fly the PocketLab Voyager and compare it to other instruments.

So when I attended the HARA launch earlier this month, I carried with me my trusty RX-16, loaded with a Quest Q-Jet D16-4 and 3 devices in the payload section - the PocketLab Voyager, a FlightSketch Mini altimeter, and a Perfectflite PNUT altimeter (the TARC gold standard). I was curious not only to see the data returned by the instruments, but also to see how well my iPhone could configure and handle 2 Bluetooth devices simultaneously (Both the Voyager and the FlightSketch Mini communicate via Bluetooth). I need not have worried about the latter, as the phone was more than up to the task, and as for the former, the instruments agreed fairly well, as you can see from the below plot.

Comparison of altitude data taken on November 14 (Click to enlarge).

Note that the Voyager ceases to return data after 140 feet - that's my fault, as I had not yet figured out how to set the instrument to autonomously record data over a span of time (What? I have to read instructions?). So it was transmitting real-time numbers via Bluetooth, which stopped once the rocket passed beyond range. However, the little bit I received looked good. A club member pointed out that the FlightSketch data is systematically lower that of the PNUT, especially below 300 feet altitude. However, the difference is less than 5 feet, so while curious, I am not bothered by it.

The FlightSketch altimeter also is capable of measuring acceleration, so let's look at that data along with the Voyager's:

FlightSketch Mini and PocketLab Voyager acceleration data for the November 14 RX-16 flight
(Click to enlarge).

Again, the agreement is good until the Voyager data transmission stops. Kind of interesting to see 22 g's at ejection, which is substantially larger than the 12 g's experienced during thrusting.

A note about the PocketLab Voyager - the documentation is not that great, as they encourage you to "experiment" with the device to figure out how it works. However, their email support is awesome, answering questions about the device operation very quickly. They were able to help me to figure out why the iPhone app was not showing the screens that allow you to configure the PocketLab to collect data offline (iPhone has to be set to "light" not "dark" mode).

I did a reflight at last week's launch, but the bad luck pervading that afternoon messed things up. Structural repairs have been made to the RX-16 and it is awaiting a new coat of paint on the fin unit. I'll be trying again at the next launch - whenever that is.

Sunday, November 22, 2020

The one where nothing goes right...

My LGM lies on the ground after its fall (Click to enlarge).

Yesterday was a very nice day, perfect rocket flying weather - clear sky, no wind, and an afternoon high of 70 degrees. So Duane and I packed our stuff and headed out to Pegasus field to launch a few rockets before the Thanksgiving holidays begin. Greg and Josh joined us, and there were quite a few launchings. The up parts generally went OK... Not so much with the landings. The short summary is that Duane and I had terrible luck on the field, and I hope it doesn't stick around for the next launch.

The first rocket off the pad was my new Estes Centurion, a foam rocket styled like a space fighter. It looks pretty darn sharp, and flew low but straight on an Estes A8-3.

Centurion on pad (Click to enlarge).
Centurion clears the rod (Click to enlarge).

Duane's 2019 Christmas rocket followed mine, heading up into the blue on a D12-3. We saw the model arc over and waited for ejection to occur. And waited, and waited, and waited... Right up to the point where the rocket smacked headlong into the ground, popping a fin off and squishing old Frosty's head pretty good. Damage is repairable, but I bet the snowman has a terrible headache.

Duane with his Xmas rocket
(Click to enlarge).
Up, up, and away (Click to enlarge)!

Frosty has a headache (Click to enlarge)!Greg shows off his Star Wars outfit
(Click to enlarge).

Next was Greg. He brought his 1990's retro Estes Naboo fighter, complete with pad and R2-D2 controller. Up it went and it came down safely under a partially deployed parachute. All in all, a good flight; kinda neat to see one of the old Estes Star Wars models fly.

Duane's Cherokee F is always a crowd pleaser, being an very nice looking upscale of the Estes model (Have I mentioned that Duane is a Cherokee fanatic, with several versions in his rocket stable?). This time it was prepped with an Aerotech F52 reload and a Jolly Logic Chute Release - which, as it turned out, would not be needed. In the saddest flight of the day, the forward closure of the motor case failed right after launch, separating the payload section from the sustainer - which was barbecued by the flame going forward through the rocket. I could not bear taking pictures of the aftermath; the fried remains were too pathetic. Needless to say, Duane was not a happy camper. But he soldiered on - and found yet more grief.

The motor in the Cherokee-F ignites
(Click to enlarge).
The payload section coupler appears as the
forward closure fails (Click to enlarge).

Josh had mixed luck yesterday - his 3D printed Y-Wing broke apart on a hard landing, but the Estes Multiroc had a pretty good flight (even found the glider). His Starbase Starcruiser flew well on a Q-Jet, but the lad has yet to perfect his cluster technique. Despite the use of low current Q2G2 igniters, only one motor in his NASA Deuces Wild lit, causing the model to arc over into the ground - just like it did at the club launch a couple of weeks ago. Everything went fine with the flight of the Fliskits ACME Spitfire, but his 2 stage Estes Supernova had a slight issue. The booster fit too tightly into the upper stage, so that the 2nd stage motor blew the lower motor right out the back of the first stage, scorching the booster a bit. It hung on throughout the flight.

Josh's Y-Wing gets going (Click to enlarge).
The Multiroc starts up the rod
(Click to enlarge)
The Starbase Starcruiser rises on a black
pillar of smoke (Click to enlarge).
Uh oh (Click to enlarge)!

Josh's ACME Spitfire on a D12
(Click to enlarge).
The 1st stage in the Supernova ignites
(Click to enlarge).

Duane hoped to reverse the recovery failure trend by flying one of his reliable TARC rockets. The model shot off the pad, attaining a respectable altitude. We saw it arc over and then heard the rocket whistle in as it plunged straight into the ground - it was buried so deep that Duane had to struggle to pull it from the Earth. As Dr. McCoy would say, "It was dead, Jim." I was beginning to feel extremely sorry for Duane, but, determined to have a successful flight, he pulled out his Estes Cherokee E and loaded it on the pad. It too flew straight as an arrow, but the parachute partially unfurled, and the rocket had a hard landing on the asphalt entrance to the Blue Origin parking lot. 2 fins broke off, - that was it for Duane. He sadly loaded his corpses and casualties into the SUV and watched the remaining few flights, refraining from some colorful language because of the presence of Josh and his mother.

Duane hooks up the igniter (Click to enlarge).
Duane's TARC rocket clears the rail
(Click to enlarge).

Which brings it back to me and my remaining two flights. These would not go as well as that of the Centurion.

In an attempt to get some HD footage of staging, I had outfitted my Estes LGM with a booster and the camera from the Estes Astrocam. The C11/B6 motor combination propelled the model to a decent altitude, but the old rubber shock cord broke at ejection, leaving the body/camera to fall horizontally (thank goodness!) and the nose cone to sail off into the sunset with my nice new Apogee nylon parachute. Fortunately, I was able to replace the nose cone but the camera footage did not yield anything useful. Apparently the camera was tilted just enough to miss the booster falling away.

The LGM blasts off (Click to enlarge).
My RX-16 under Q-Jet power
(Click to enlarge).

Frame showing staging from camera on the LGM (Click to enlarge).

All the failures of the day caused me to look long and hard at my Centuri RX-16 clone, which was loaded with a Quest D16 and about $200 in electronics (FlightSketch Mini altimeter and the PocketLab Voyager). The rocket had had a perfect flight at the HARA launch, so I figured I'd give it a go. I almost backed out as I loaded the model on the pad, but talked myself into proceeding. The rocket sped up into the blue sky and I breathed a sigh of relief when I saw the orange nylon parachute come free. However, it would not open - the rocket kept falling and the parachute stayed closed, wriggling about as if to say "Should have not done this." The RX-16 hit the ground hard enough to break a fin, adding another strand to the day's awful string of recovery failures. Even worse, the landing jarred the altimeter, which gave nonsense readings of negative 500 feet. And then, flustered as I was, I must have accidentally wiped the PocketLab's memory trying to download the data into my laptop. Sigh...

I laid my casualties next to Duane's in the vehicle, and we left the field wondering how such a beautiful day could give birth to enormous carnage. The RX-16 repair is under way, and I am still trying to figure out how I wiped the Voyager's memory. In a way, I envy the Voyager - a memory wipe of yesterday from my brain would be good.

Here's hoping the next launch goes better!

Sunday, November 15, 2020

A perfect day for flying...

Flyers begin to assemble for the pre-launch briefing (Click to enlarge).

Yesterday HARA had its first launch of the 2020-2021 season - the skies were clear and blue, the winds relatively tame and the temperature perfect. We had lots of folks show up, and man, there were a bunch of of certification flights. Art and Allen took care of over 20 level 1 and level 2 certifications, which shows in the H motor tally - 26, most of them H115 sparkys. I flew two modrocs, both of which were heavily instrumented. A description of those flights will come in a later post, but for now, enjoy the very pretty pictures from yesterday - pretty because most of them were taken by others with great cameras, unlike my shots with the iPhone camera. They're OK, but can't compare to what real photographers can produce.

Members of a college team waiting their turn to launch (Click to enlarge).

Let's start off with Chuck's flight of his Dynasoar Fireball XL-5. Frank Burke makes these beautiful kits, and I only wish had the RC skills to fly them (I learned long ago I can only handle things in ballistic trajectories). The XL-5 put in a superb flight, echoing that of the Star Trek-themed U.S.S Orion, which was Chuck's first of the day. True to form, he switched to flying a couple of planes as the day wore on, much to the enjoyment of the folks away from the flight line.

Chuck's Fireball XL-5 in flight (Photo by Patrick Morrison - Click to enlarge).

U.S.S Orion doing its thing.

Chuck shows off his flying skill (Photo by Patrick Morrison - Click to enlarge).

One of the most anticipated flights of the day was that of John Kraieski's Goddard replica. This beauty awed the crowd with its flight (which was textbook, btw), and had more than one person scratching their head wondering how it flew straight.

John Kraieski's rocket in flight (Photo by Drew Hardwick - Click to enlarge).

My young colleague Josh is a true rocketeer - he built an impressive Y-Wing modroc that flew quite well. Not so much for his modified Deuce, which struggled off the pad when only one B6 motor lit (Used Estes Starters, of course). Hit the ground before ejection, but fortunately the model only had a few scratches.

Josh's Y-Wing in flight (Photo by Patrick
Morrison - Click to enlarge).
Josh's Deuce begins to arc over (Photo
by Patrick Morrison - Click to enlarge).

Vince converted a Pegasus Apollo 27 plastic model for flight. When asked by the LCO if it was to be a "Heads Up" flight, he responded with a negative. My comment was "All plastic model conversions are heads up flights." Even though it was a bit underpowered, the Apollo 27 was quite stable in the air; however,  my words proved to be prophetic when nothing came out at ejection, leaving the model to shatter upon impact with the ground. I felt sympathy for Vince - he had obviously put a lot of work into that build.

Vince's Apollo 27 leaves the rod (Photo by Patrick Morrison - Click to enlarge).

In a small preview of today's Space X crew launch, one of the flyers launched his mid-power Falcon/Dragon model, based on a paper version you can get on the Internet. Flew great, just like the real thing did today.

A Falcon 9/Dragon model heads skyward (Photo by Patrick Morrison - Click to enlarge).

The launch started at 10 AM and rockets flew all the way up to sunset at 4:45 PM - total number of flights was 88, 42 of which were high power. Not a bad day!

Another rocket takes to the air (Click to enlarge)!

Sunday, November 8, 2020

A question of supply...

Estes Yankee Clipper (Click to enlarge).

I have been making good progress finishing off builds that have languished for months. This year's 4th of July rocket, the Yankee Clipper, is finally done, and I have 4 others sitting in white primer awaiting their coats of paint. Considering they were in gray primer at the beginning of the week, that's good progress, especially when you realize that I had to sand all that primer off before applying the white. I was pretty pleased with myself as I started looking for my cans of gloss white, which I use as the base coat on all of my models.

Models in primer - from left, clone of the Estes Screaming Eagle, Estes Olympus, Jupiter-C
plastic model conversion, and the Boyce Redstone Missile (Click to enlarge).

And that's when I realized I had a problem...

I had only a couple of cans of Krylon gloss white, and those were practically empty - maybe enough for the small Screaming Eagle, but certainly not enough for the Estes Olympus and the Boyce Redstone. So I hopped onto the Internet to order a case (6 cans) of Krylon Acryli-Quik gloss white.

Only to find out no one had any...

It turns out that the manufacturer (Krylon) is suffering from a materials shortage due to the pandemic, and gloss white is backordered to the tune of 1-2 months.


Desperately looking for cans of this stuff...

I could use another paint brand like Rustoleum, but it isn't as forgiving as Krylon with regard to runs and drips; also, other folks have had poor "orange peel" or crinkled finishes. Not my thing... 

So I scoured the Internet some more, and finally located a couple of cans in a mom and pop shop up North. So I placed the order, and am keeping my fingers crossed their online inventory is accurate.

Because no one else has any.

However, things are not at a complete stop. I have a can of Testor's white to use on the Jupiter-C, so it will get moved to the front of the line while I await the arrival of more Krylon. That's probably a good thing, because it takes Testor's enamel a long, long time to dry (at least a week).

The pandemic continues to affect us in unforeseen ways...